Presently a multitude of machines designed to form cardboard boxes from previously pressed flat sheets are known. These machines all coincide in the way of forming the box. The former is introduced in a matrix upon which the box is formed and the box is subsequently ejected.
The circumstance that the former is extensible is due to the need to reduce its size in order to come out of the matriz once the box has been formed when the box has horizontal bridges. If the box does not have horizontal bridges, the former could be stationary, in other words, not extensible.
Presently, extensible formers have complicated pneumatic expansion devices that have bearings, pneumatic cylinders, etc. and besides they are not interchangeable; in other words, as there is a large number of measurements of boxes it is necessary to have the corresponding formers.
If we take into account the number of sizes of boxes that exist, we are talking about having an infrastructure of spares which is enormous with all the inconveniences that this involves.